Novak Djokovic was captured on video having a talk with a fan during his pre-match practice session.

Novak Djokovic strolled past Denis Kudla 6-3, 6-4, 6-2 to reach the US Open last 16 on Friday. However, before the start of his match, the World No.1 appeared to get involved in an angry exchange with a fan. The 16-time Grand Slam champion was captured on video speaking to a fan during his warmup session before facing his American opponent in the third round at the Arthur Ashe Stadium. In the video, Djokovic is seen walking over to the end of the court and after a brief discussion, is heard saying, "I'll come find you. I'll find you after. Trust me, I'll find you."

Asked about the confrontation he called a "little chat", Novak Djokovic said he would locate the heckler, "To have a drink. I liked the guy. I'm going to buy him a drink."

As to exactly what was said, Djokovic kept that between drinking buddies, but did say it was beneficial to his overwhelming effort in ousting Kudla.

"We'll keep it between us. But he definitely helped me. He doesn't even know, but he did help me," Djokovic said.

"I'm not going to talk about it. I think he did me a favor. Even maybe he didn't want to do me a favor, he did me a favor, big favor."

Djokovic even had a couple of over-the-top fans against him in the match, but those he accepted as part of the Arthur Ashe Stadium atmosphere for night matches.

"Night sessions, New York, crowd gets into it," he said. "A couple guys that had a couple of drinks more than I guess they were supposed to. But it was all good after."

The Serbian star, who has won four of the past five Grand Slam events and 16 overall, advanced to a fourth-round meeting with three-time Slam winner Stan Wawrinka. They haven't played since the Swiss 23rd seed beat Djokovic in the 2016 US Open final.